Night vision imagers operate to sense reflected visible or short wave infrared (SWIR) light for high resolution images and long wave infrared (LWIR) radiation for thermal imaging. Some night vision imagers, such as the U.S. Army's Enhanced Vision Goggles (ENVGs) and the multiple-adaptable night tactical imaging system (MANTIS) sense both short wave and long wave radiation simultaneously as both wavelengths provide independent image information.
These existing systems require separate sensors for detecting both SWIR radiation and LWIR radiation. The use of two sensors results in the approximate doubling of both the size and the weight of these systems. When employed in helmet-mounted or hand-held night vision systems, the additional size and weight can present a rather severe disadvantage to the user. In addition, it is typically a requirement that night vision sensors operate at or near ambient temperature in order to reduce the size, weight, and power of the sensor. Therefore, a system that combines visible or SWIR radiation sensing with LWIR radiation sensing is most useful as a portable night vision detector when capable of operating at or near ambient temperatures.